cotteell



(No Model.)

0-. P. GOTTRELL.

AIR SPRING OR GUSHION FOR PRINTING MAOHINES.

Patented May 29, 1888.

Inverziremam/ .5";-

N. PEI'ERS, mwmm mr. wwnns m n. c.

UNIT D STATES PATENT OFFICE.

CHARLES P. GOTTRELL, OF STONINGTON, CONNECTICUT, ASSIGNOR TO 0. B.OOTTRELL & SONS, OF SAME PLACE.

AIR SPRING OR CUSHION FOR PRINTING MACHBNES.

SPECIPICATION forming part of Letters Patent; No..383,630, dated May 29,1888.

Application filed O tobcr 26, 1887. Serial No. 253,425.

To all whom it may concern.-

Be it known that I, GHARLEs P. COITRELL, of Stonington, in the county ofNew London and State of Connecticut, have invented a new and usefulImprovement in Air Springs or Cushions for Printing-Machines, of whichthe following is a specification.

In those printing presses or machines which comprise a rotaryimpression-cylinder and a reciprocating bed operated by means of amangle motion or analogous gearing other than a crank andconnection-rod, it is common to employ for arresting the bed at each endof its stroke an air spring or cushion comprising a cylinder and aplunger fitted thereto, the said parts being secured one to the bed andthe other to the frame of the machine. The plunger or piston has veryfrequently consisted of a simple disk or head fitted upon a screwsecured to the frame and the cylinder has been secured to the bed, andin such a construction the piston or head has been adjusted by turningthe screw, so that with a given movement of the bed the air between thebottom of the cylinder and the piston or head will be subjected to anydesired degree of pressure.

The object of my invention is to provide means whereby the quantity ofair which is entrapped in the cylinder when it enters upon the plungermay be varied, so that the resistance opposed to the movement of the bedwill be varied, not by varying the point at which the cylinder passesonto the plunger, but by varying the quantity of air entrapped in thecylinder by the entrance of the cylinder upon the plunger and the spacewherein such air may be compressed.

The invention consists in the combination, with the bed and frame of aprinting-machine, of an air-spring mechanism for stopping the bed at theend of its movement, consisting of a cylinder and a cup-shaped plungerhaving its open end presented toward the cylinder, one of said two partsbeing secured to the bed and the other to the frame, and a head fittingthe interior of the cup shaped plunger and movable lengthwise therein tovary the airspace between the cylinder and plunger. The plunger may besecured in fixed position to the frame, and the head which isfitted inthe plunger may be adjusted by a screw which (No model.)

Similar letters of reference designate come 65 sponding parts in bothfigures.

A designates the bed, and B aportion of the frame.GDarerespectivelythecylinderandplunger. of my improved air-cushion,which are secured one to the bed and the other to the frame. In thisexample of the invention the cylinder 0 is secured to the bed A by meansof flanges c, as shown in Fig. 2, and the plunger D is secured by abracket, D, to the frame 'B of the machine. The plunger D does notconsist simply ofa head or disk-like piston fitted to the cylinder, butis of cup shape, as shown in Fig. 1, having its open end presentedtoward the open end of the cylinder, and provided at its inner open endwith a packing, d, of any suitable form to tightly fit the cylinder.

The novelty of myinvention consists, essentially,in fittingahead, E,within the cup-shaped plunger, which is bored out to form a snug fitbetween the head and the interior of this plunger, and by ascrew, F, Iprovide for shifting this head lengthwise of the plunger, so as to varythe capacity of the plunger between its open end and the head E. As hererepresented, the screw F, which is provided with a hand-wheel, F, forturning it, presented at the end of the machine, is threaded in theclosed back end of the plunger D at d, as in a nut, and is connectedwith the head E at 6, so that it may be turned in the head; and it willtherefore be seen that by operating the screw in one or other directionthe head E will be shifted in one or other direction lengthwise of theplunger D, and by such shifting the amount of air which will beentrapped between the plunger and cylinder at the time the cylinder ICO' strikes the plunger in moving toward the right of the drawings will beincreased or diminished, as may be desired. When the head E is shiftedtoward the right hand of the drawings, so as to increase the spacebetween the open end of the plunger D and the head E, alarger volume ofair will be entrapped between the cylinder and plunger when the cylinderfirst strikes the plunger, and a greater space will be afforded in whichto compress the air, and a given movement of the cylinder upon theplunger will meet aless resistancethan it would if the head E wereshifted toward the open end of the plunger and a correspondingly lessvolume of air trapped in the cylinder Oand aless space afforded whereinto compress the air.

In air-springs, as heretofore constructed, where the plunger consistssimply of a head or disk-like piston upon a screw, the volume of airentrapped in the cylinder is always the same at the moment it entersupon the plunger, and the resistance opposed by such an airspring hasbeen varied by shifting the plunger backward or forward, so that thecylinder will strike it earlier or later in the movement of the bed.

I have represented the usual vacuum-valve, G, which in my invention isattached to the pipe G, extending through the closed back end of theplunger D and through the head E. This pipe may be fast in the closedend of the plunger, and the head E may slide upon it as it is movedlengthwise of the plunger by the screw F.

H designates portions of the usual bearers 3 5 or shoes which are uponthe bed A, and I designates cross portions of the framing, which formthe tracks or ways for these bearers or shoes.

What I claim as my invention, and desire to 0 secure by Letters Patent,is-- f 1. The combination, with the bed and frame of a printing-machine,of an air-spring mechanism for stopping the bed at the end of itsmovement, consisting ofa cylinder and a cup- 45 shaped plunger havingits open end presented toward the cylinder, one of said two parts beingsecured to the bed and the other to the frame, and a head fitting theinterior of the cup-shaped plunger and movable lengthwise 50 therein tovary the air-space between the cylinder and plunger, substantially asherein described.

2. The combination, with the frame B and bed A, of the cylinder G on thebed, the cupshaped plunger 1) on the frame, the head E, fitting theinterior of the plunger, the screw F, for shifting the head lengthwiseof the plunger, and the vacuum-pipe G, and valve extending through thehead and back of the plunger, substantially as herein described.

CHAS. P. CO'ITRELL.

Witnesses:

D. H. CHAMPLIN, A. R. STILLMAN.

